(35 ILCS 5/601.1) (Ch. 120, par. 6-601.1)
    Sec. 601.1. Payment by electronic funds transfer.
    (a) Beginning on October 1, 1993, a taxpayer who has an average monthly tax liability of $150,000 or more under Article 7 of this Act shall make all payments required by rules of the Department by electronic funds transfer. Beginning October 1, 1993, a taxpayer who has an average quarterly estimated tax payment obligation of $450,000 or more under Article 8 of this Act shall make all payments required by rules of the Department by electronic funds transfer. Beginning on October 1, 1994, a taxpayer who has an average monthly tax liability of $100,000 or more under Article 7 of this Act shall make all payments required by rules of the Department by electronic funds transfer. Beginning October 1, 1994, a taxpayer who has an average quarterly estimated tax payment obligation of $300,000 or more under Article 8 of this Act shall make all payments required by rules of the Department by electronic funds transfer. Beginning on October 1, 1995, a taxpayer who has an average monthly tax liability of $50,000 or more under Article 7 of this Act shall make all payments required by rules of the Department by electronic funds transfer. Beginning October 1, 1995, a taxpayer who has an average quarterly estimated tax payment obligation of $150,000 or more under Article 8 of this Act shall make all payments required by rules of the Department by electronic funds transfer. Beginning on October 1, 2000, and for all liability periods thereafter, a taxpayer who has an average annual tax liability of $200,000 or more under Article 7 of this Act shall make all payments required by rules of the Department by electronic funds transfer. Beginning October 1, 2000, a taxpayer who has an average quarterly estimated tax payment obligation of $50,000 or more under Article 8 of this Act shall make all payments required by rules of the Department by electronic funds transfer. Beginning on October 1, 2002, a taxpayer who has a tax liability in the amount set forth in subsection (b) of Section 2505-210 of the Department of Revenue Law shall make all payments required by rules of the Department by electronic funds transfer. Beginning on October 1, 2002, a taxpayer who has a tax liability in the amount set forth in subsection (b) of Section 2505-210 of the Department of Revenue Law shall make all payments required by rules of the Department by electronic funds transfer.
    (b) Any taxpayer who is not required to make payments by electronic funds transfer may make payments by electronic funds transfer with the permission of the Department.
    (c) All taxpayers required to make payments by electronic funds transfer and any taxpayers who wish to voluntarily make payments by electronic funds transfer shall make those payments in the manner authorized by the Department.
    (d) The Department shall notify all taxpayers required to make payments by electronic funds transfer. All taxpayers notified by the Department shall make payments by electronic funds transfer for a minimum of one year beginning on October 1. In determining the threshold amounts under subsection (a), the Department shall calculate the averages as follows:
        (1) the total liability under Article 7 for the
    
preceding tax year (and, prior to October 1, 2000, divided by 12); or
        (2) for purposes of estimated payments under Article
    
8, the total tax obligation of the taxpayer for the previous tax year divided by 4.
    (e) The Department shall adopt such rules as are necessary to effectuate a program of electronic funds transfer and the requirements of this Section.
(Source: P.A. 91-541, eff. 8-13-99; 92-492, eff. 1-1-02; 92-846, eff. 8-23-02.)